Replacing Johnson Lower Unit and Shift Rod Adjustment

[Cdogtx]

I have a 1990 Johnson GT150 that I am replacing the lower unit on. The lower unit I am replacing it with came off of a 1996 Johnson 175. This shift linkage a little different so I pulled my old one out to put in the new unit. I adjusted the length to where the old one was according to turns. When I put it together it will not quiet go far enough in either direction to go in gear. I've adjusted the cable and can get forward or reverse, but not both.
Can someone tell me what the height of the shift rod is suppose to be on a 20" lower unit. I thought I would try that unless anyone has another idea?

 

[emdsapmgr]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

You are trying to put a looper lower unit under a crossflow engine. I've not done that and don't know if it will fit or not. The service manual for an 86 crossflow has the following shift height spec: 22 1/16" +- 1/32" This is measured from the centerline of the shift rod hole to the top of the gearcase. My guess is that this measurement is the same as for an 85 engine.

 

[boobie]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

Check the top secret files at the begining of this forum for shift rod heights.

 

[Cdogtx]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

Thanks for the reply, When I purchased the lower unit I was under the impression that all the V6 gear cases would work after 78'. This may not be true. I have it bolted up and everything seems the same except the shift linkage. I will take it back off and adjust the length to the proper specs, and if that doesn't work, I guess I will have a lower unit for sale

Thanks again for the info

 

[Cdogtx]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

Check the top secret files at the begining of this forum for shift rod heights.

I'm sorry, but being new to this forum, I don't know what you mean by top secret files

 

[Cdogtx]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

Found it..thanks....now I guess the question is, will it work all. Looper going on a crossflow?

 

[emdsapmgr]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

The gearcases probably look nearly identical. I'd verify the spline count on the drive shafts, the upper/lower heights of the splined area-comparing both drive shafts against each other. Also compare the total driveshaft height. Hope it works out.

 

[Cdogtx]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

Thanks to all of you for the replies. I adjusted the shift linkage, check the spline and drive shaft length. The drive shaft for the 60 degree looper was a little shorter than my crossflow motor was so I had no problem putting it together. Seems like everything is going work fine
Thanks again to everyone.

 

[seahorse5]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

You will have a driveshaft mismatch unless you changed it to your 1990 style before installing the newer lower unit.

The '96 version has a differently machined driveshaft below the splines to allow for the oring on a 1996 crankshaft to seal the splines from water. The '90 engine does not have a crankshaft seal but uses an o-ring on a groove on its driveshaft below the splines to do the sealing. This is besides the difference in the length of the shafts. If not taken care of, you may have corrosion buildup and/or spline wear problems

 

[Cdogtx]

Re: Replacing Johnson Lower Unit and Shift Rod Adjustment

Thank you seahorse5. I never thought about the oring groove having to seal to the crank. Looks like I'll have a very nice looper V6 lower unit for sale
I appreciate all the replies and help from everyone.